Centrifugal casting machine and method



May 28, 1935. w. D. SARGENT 0 4 CENTRIFUGAL CASTING momma AND METHOD Filed Nov. 6, 1951 2 Sheets-Sheot 1 IIIIWIIII II IIII I I I I: I 1 II I I I III I I I I II I I I I I I/ I 71/1 INVENTOR 0.,Saz' a IMS'ATTORNEY x ,1 1 I II llliam I/I I. II I II I I III, II I I I I I "II I I I I 1 May 28, 1935. w. D. SARGENT CENTRIFUGAL CASTING MACHINE AND METHOD 2 Sheets-Sheet 2 Filed Nov. 6, 1931 W'llz $33 M ,I am W wAnoRNms Patented May 28, 1935 PATENT OFFICE ev omv'ramuoar. oss'rmo AND METHOD William D. Sargent, Newark, N. 1., assignor, by

assignments, to Dural'cr (Ina), Dover,

Del., a corporation of Delaware Application November 6, 1931, Serial No. 573,353 4 claims. (01.- 22-45) The present invention. relates to methods and apparatus for casting centrifugally and embodies. more specifically, an improved centrifugal casting method and apparatus by means of which a more perfect and more dense casting may be produced than in methods and apparatus heretofore designed. .The invention further embodies an improved machine and method for casting twodifferent metals in a single casting operation. More .speoiflcally, the invention embodies an im proved 'method and device for casting centrifugally wherein, prior to the directing of the molten metal into the mold, form or other means in which the metal is to be cast, the quantity of metal to be cast is distributed substantially uniformly adjacent the mold or form in which the casting is to be effected, rotation of the device to direct themolten metal'into'the mold either being eifected prior or subsequently thereto.

In devices of this character recently designed for centrifugal casting the pouring has been eifected upon a plate while the mold is rotated at high speed, the-centrifugal force imparted to. the molten metal through contact with the pouring plate causing the same to fly outwardly against the interior of the mold and be held in such position untilcrystallization of the metal hastaken place. The uneven action resulting from contact of the stream of molten metal with a rapidly uniform distribution of the liquid inetal'in the mold. It is therefore contemplated, in connection with a mechanism for casting centrifugally, to pour the quantity of metal to be cast into an interior trough of uniform dimensions, rotation of.

the mold to perfect the casting operation being effected either prior or subsequent thereto. This method results in'a highly uniform casting and a generally more satisfactory casting operation as 40 will be described in greater detail hereinafter.

" An object of the invention, accordingly, is to provide'a centrifugal casting machine and method of oasting centrifugally' wherein the molten metal to be cast is treated in such fashion as to result 5 in a more uniform and'dense casting than those now obtainable.

A further object of the invention is to provide a device of the above character wherein means is provided for effectively pouring the metal into an 50 annular trough of uniformdimensions adjacent the mold whereby upon rotation of the trough and mold the metal moves into the mold by centrifugal force and isdisposed uniformly-in the desired. position therein.

55 Further objects, not specifically enumerated position shown in Figure rotating plate causes surging and results in a nonabove, will be apparent as the invention is described in greater detail in connection with the accompanying drawings, wherein:

Figure 1 is a view in side elevation, partly broken away and in section, showing a centrifugal 5 casting machine constructed in accordance with the present invention.

Figure 2 is a plan view of the pouring table shown in Figure 1.

Figure 3 is a view in section, taken on line l-I of Figure 2, and looking inthe direction of the arrows.

Figure 4 is aview in section, similar to Figure 3, showing a modified form of pouring table.

Figure 5 is a detail view showing the manner in which the molten metal moves from the pouring trough into, the mold upon initial rotation 4 of the latter.

Figure 6 is a view similar to Figure 5 showing the manner in which the metal moves from the 1 into the mold as the speed of rotation of the mold is increased.

Figure 7 is a view similar to Figures 5 and 6, showing the positionpf the molten metal when the centrifugal force thereof has caused the same to flow into the mold into the casting position.

Figures 8 and 9 are views similar to Figures 5, I 6, and '7 showing modified forms of pouring troughs constructed in accordance with the present invention, .the molds being provided with welding strips to facilitate the mounting of the casting upon any desired support.

,Figure 10 is a view of an improved form of trough wherein the depth of the trough isvaried to provide a casing of suitable character.

Figure 11 isa view similar toFlgure 1 showing a modified formof mold and pouring table.

Figure 12 is a view similar to Figure 11, showing a further modification-of the trough construction in accordance with the present invention, 49 the construction being adapted for progressive pouring of a plurality of metals. I

Figure 13 is a segmental view similar to mum .12 showing the position which the metal assumes shape, either annularor disc shape in profile as on which the mold or band is supported. I

I resulting casting of great uniformity is produced.

will appear hereinafter, the construction first described being of generally annular outline having a central recess I4 formed therein. Adjacent the interior of the pouring table l2 and defining. the aperture or recess I4, is an annular flange a l5 having two flat surfaces l6 and I1, respectively'. These portions of .the flange l5 provide widened portions within which the pins or bolts l3 are received to strengthen the pouring table.

'Adjacent the outer periphery of the pouring table a-cylindrical rim I 8 is formed, the rim being spaced from the flange IE to form an annular trough l9. Upon the inner periphery of the rim l8,..a shoulder 20 may be formed to serve as a guide and positioning element for a band or form 2| in which the metal is desired to be cast. The operation of the mechanism may include the heating of either the pouring trough or mold or both of them in accordance with methods previously developed by applicant, the heating being either for the purpose of maintaining a predetermined heat balance in the metal and associated elements, or for the pu p se of promoting an efiective union between the mold and cast metal- It will be understood therefore that the heating of the mold and/or trough constitutes no part of the present, invention.

In the construction shown in Figure 4, the pouring table and .rim l8 are shown as provided with a cylindrical flange 32 which serves as a backing for the band or form 2|. This backing may facilitate the maintenance of a desired heat in the form or band and also facilitate the positioning thereof upon the table.

The action of casting in the above fashion will be seen to be somewhat similar to a fluid forging process wherein liquid metal is shaped from a ring with a cross section approximately semicircular into a thin cylindrical bandof larger diameter before crystallization by'means of the centrifugal action. The method may be effected in combination with either a mold or band, either heated or unheated. Any suitable refractory material or metal that will withstand the heat of molten metal would be satisfactory for the pouring table, the trough formed therein. either being on the level of, above, or below the table The metal in the trough will move without unnecessary violence into the mold or band and a As rotation tak es place and the mold accelerat-' ed the fluid in contact with the trough is started ,in motion while the balance of the fluid remains stationary. At the same time, the upper surface of the fluid changes its position proportionately as the surface in contact with the trough drags the adjacent molecules of fluid into rotation and subjects them to. centrifugal action. This condition is illustrated in Figure 5.

By the time the contour of the fluid has assumed the shape shown in Figure 6, much more of the fluid is rotating at the speed of the trough and the radial impact of the molecules is increasing so that they seek the parts of the mold most remote from the center and fill all recesses in the mold to which they have radial access,

, the fluid particles being piled up on each other until the entire mold is'filled to the limiting lip as shown in Figure 7. The trough as formed provides a means of gradual acceleration of the fluid, attaining piactically the speed of the mold by the time that it enters the peripheral parts thereof thus enabling the complete filling out of all contours of the mold for casting operations such as the casting of gears and sprocket wheels. I

In comparing this centrifugal method of casting with other possible methods of casting gears, sprocket gears and other similar objects in a stationary mold, it would be similar to providing a stationary mold in which liquid could be poured pressure exerted in'such fashion would not resuit in a denser structure at the remote surfaces (toothed surfaces) which condition is aiways obtained by centrifugal casting.

By the herein described trough method of pouring it is possible to cast centrifugally'with a certainty of obtaining definite results. Many types of castingsin addition to gears, sprockets, etc., may be formed, as well as castings, the exteriors of which may be required to be of an irregular shape in which shape the irregularities may be formed in steel, rolled, forged and pressed, and the cast metal fused with the steel. On the other hand, the sprocket wheel or other object possessing a wearing surface may be made of centrifugally cast iron by the process described herein and thereafter placed in a heating type of machine, steel then being cast by the centrifugal method described herein against the iron and fused thereto.

It will be seen that a great numberand variety of forms and objects may be cast, as well as a vast number of combinations of hard and soft metals. or metals having other characteristics. These operations have hitherto never beenpossible since the results attained depend on a perfectly uniform method of casting the metal into the mold or' form by centrifugal force;

It will be apparent that the form or-profile of the trough may be varied in accordance with the particular type of casting operation in which it p is to be utilized, as may the rate of'acceleration of the motor to effect the desired speed of pouring. In case it is desired to fill the mold quickly, the slope of the pouring trough may be gradual as shown in Figure .8 or, should it be desirable to cause the metal to attaina higher velocity before being cast into the mold, the pouring trough shown in Figure 1 may be'utilized and the rate of acceleration of the same reduced as desired. In Figure 9, a pouring trough is illustrated having a section between the extremes illustrated in Figures 1 and '8.

It will be apparent that a welding ring may be placed in the lower part of the-mold and be subiect to the heating action of the film of metal which is cast over it as the table is revolved at a predetermined speed. If the ring is perforated or otherwise interlocked with the cast iron it becomes either partially orwholly fused on its exposed surfaces and constitutes a welding ring to which the diaphragm of the drum may be welded. This is illustrated in Figures 8 and 9, wherein in Figure 9, a welding ring 50 is placed in a mold 5|, the ring being provided with a plurality of apertures 52. As the metal 53 is cast from the pouring trough 54, the welding ring is secured in its proper position with respect to the mold. In Figure 8 the annular insert 55 isshown as having a fiat outer periphery it and arounded accepts inner periphery 51 whereby the insert will be effectivelyunited with the casting and afford a cylindrical surface of steel to which may be weldto permit withdrawal'of'thetrough leor Figure has ed a ring or disc for mounting the casting.

In Figures 8 and 9, the mold is shown as of the placed closer density than the casting casting having greater produced by the construction shown in Figure 7,

in as much'as the trough is of greater depth. A greater centrifugal force will be required to lift the metal in the trough and direct it outwardly into the-shell than the force required in the construction shown in Figure '1. Itwill be apparent, in this connection, that certain of the factors determining the characteristics ofthe comparatively slowly, the I by providin a receptacle the film of 'troughvinto the mold; It

mold or form,

and the potential energy of the cast metal include those of speed and dimensions of the trough. The escape from the trough, the greater the density of the casting will he and the more sudden will the casting. of the metal take place from .the will be apparent that the nearer the outer rimof the trough is to the the greater will be the lineal speed of rotation'cf thejduter' surface of' 'the metal, and the deeper the trough, the more effect the contactof this rapidly revolving surface will-have upon the body of the. metal. An additional factor bearing upon the time phase of the operation mass of metal is that of varying the width of the trough. Variation of these conditions affects the thickness of the stream flowing from the trough to the mag. The centrifugal force the metal contains is us increased by forming the outer wall of the trough immediately adjacent the mold or shell and by forming the trough as deep as practical considerations will allow. This is important in case a fusing action is desired, the above factors determining the intimacy of the junction or union'between the cast metal and the shell. The factors specifically enumerated as partially de termining the character. of the inetal and the casting operation are not to be understood to be the onlyv factors entering into the operation aforesaid as other and additional factors not now apparent may also partially determine these characteristics.

Should it be desirable to fill the mold or form trough may be formed refractory or pouring table, this receptacle preferably having ,a cone-shaped center with walls of'sufllcient depth to insure the storing up of sufiicient centrifugal force in the metal before metal passes over the portion of the refractory intervening between the wall and the mold or'form. The construction shown inFlgure 11 is illustrative of the foregoing wherein a refractory 23 is. provided with pouringtable or shell 24 and a central recepa suitable mold or tacle 2|. A conical vlded to impart a centrifugal force to the metal.

higher the metal climbs to in the center of the and great circumferential length,

central member 28 is pro- This construction would prove quite desirable in filling a mold having a cavity'as shown, the fillspective metals are poured into the respective" troughs 28 and 29. The metal in the outer trough 29 will be cast before the metal within the trough 28 and the depth of these troughs may be varied. to provide the desired' characterunif'ormly if the metal is cast shown in Figures 12 and' troughs 28 and 29, the-num istics in the respective layers in the resulting casting, The inner trough, rotating at a lesser speed than the outer troughjwill not discharge ing of the be increased until the casting ofthe metal 'within the inner trough has been effected.

its contents into the mold until '-the metal within f the outer trough has been cast. After the castfirst metal, the speed of the mold may It will thus be seen that layer. casting may be accomplished effectively by means of the present invention, as well as the effective regulations of the density of the cast metal.

While the invention has been described with specific reference to'the accompanying drawings,

it is not to be limited, save as defined in the appended claims. I claim as my invention:

1. A casting device comprising-rotatable means for supporting a mold; said means being formed with a plurality of annular troughs of smaller diameter than the mold to receive metal to be directed into the moldby centrifugal force due to its rotation.

2. A casting device comprising a rotatable means for supporting a mold open on its inner side, said means provided with a block having a relatively narrow annular pouring trough closely adjacent to and inwardly of said mold to receive metal in the form of an annular stationary ring, whereby upon rotation a substantially uniform force is applied simultaneously to all metal contained in the trough to discharge the same substantially instantaneously in a direction radial, to all parts of the face of said mold.

3. A casting device comprising a rotatable an? nular mold and an annular pouring trough encircled therewithin and adapted to rotate therewith, said pouring troughbeing relatively nar:

row, closely adjacent the mold, open at its top, and

having its outer lip in a plane passing through the-mold whereby a chargeof metal placed in the trough while stationary may be substantially uniformly accelerated when rotated to substantially simultaneously transfer the entire charge into the adjacent mold.

'4. The method of centrifugal casting which comprises pouring molten metal into a stationaryannular trough of relatively small cross section rotating said metal about a long radius by rotating said trough and substantially simultaneously and uniformly accelerating all metal in the trough, and substantially simultaneously discharging all the metal radially and uniformly into a closely adjacent encircling rotating mold.

' WILLIAM o. smear. 

